Seeking horn array loudspeakers with a maximum price of $17,500.00 per pair.

If I were in your shoes with that budget, my choice would be to take that dough and get a nice pair of custom veneer Volti Lucera's or a used pair of Rival's then spend the remainder on tube amplification. I had the Rogue RP-1 and liked it very much. Paired with something from Cary, or Quicksliver would be pretty awesome. I have yet to hear a loudspeaker that knocks dynamics, tonal quality, and midrange out of the park like Volti's do. IMO of course. 

sounds rich, full bodied and dynamic at 50-55 decibel levels

I question if that is possible with any loudspeaker.

Another recommendation for Volti Rivals. I really enjoy mine. Not even sure that you will have to turn on your big Bryston amp to get to 60 db…. You might need 1/10 of a watt on peaks w/ them at 98+ db sensitivity. Seriously, some amps don’t sound their best until significant power is drawn from them so you may consider a lower powered amp & maybe tubes.

Happy Khorn owner here. Ecstatic owner when subs were added. Easy to find latest iteration new/demo/used. With subs I was all in for under your budget.

Be that as it may I would think the Volti Rivals (with or with out subs) would thrill.

The big honking amp might be not quite the right fit????

used Avantgardes

https://www.hifishark.com/search?q=avantgarde